The invention relates to a roughness measuring instrument.
Roughness measuring instruments are in use in the workshop and in business for determining characteristic roughness values of workpieces. For example, a roughness measuring instrument is known from German Patent DE 41 32 724 C2. It comprises a feeder device and a roughness sensor moved by the feeder device. The signals generated by the roughness sensor are delivered to an evaluation device, in order to determine characteristic roughness values.
The roughness sensor has a diamond tip, supported on a lever arm and guided in sliding fashion over the workpiece surface. The motions of the diamond tip caused by the surface roughness are detected by a suitable sensor and converted into electrical signals. The magnitude of the deflection of the diamond tip corresponds to the signal amplitude of the sensor device. From the electrical signals picked up, the characteristic roughness values are determined. Care must therefore be taken to assure that the electrical signals in their magnitude depend in a defined way on the roughness. To that end, the roughness measuring instrument is subjected to a calibration.
The calibration must be monitored from time to time to assure that the characteristic roughness values ascertained by the device are reliable. This should be done in as simple a way as possible.
With this as the point of departure, it is the object of the invention to create a reliable roughness measuring instrument.